Learn more about the causes of depression:

Transcript

What causes depression?

DR. MYRNA WEISSMAN: Now, depression is a biological disorder. It's not all in your head. But the triggers of depression, and whether you have an episode and when you have an episode or an onset are probably related to environmental factors. And those are loss of attachments and stress and loss in your life.

You might think about depression a little bit like you think about diabetes, which is a genetic disorder. Late-onset diabetes is a complex genetic disorder. However, if you eat right and exercise, you may never get diabetes. But if you don't, you may get late-onset diabetes in adolescence. And that's what we're seeing now. Depression might be just like that.